Electro-mechanical position indicator

ABSTRACT

The indicator consists of a coil wrapped around an iron core and a visual target which is rotatably and displaceably supported and which contains a permanent magnet. Upon reversal of the magnetic field in the iron core produced by the coil, the permanent magnet of the visual target is repelled, rotated 180* by the magnetic forces and again attracted. The new position of the visual target is thereby fixed, even if current no longer flows through the coil.

United States Patent [191 Michels I [5 ELECTRO-MECHANICAL POSITlON INDICATOR [75] Inventor: Hans Michels, Erlangen, Germany [73] Assignee: Siemens Aktiengesellschaft, Munich,

Germany 22 Filed: Feb. 29, 1972 21 Appl. No.: 230,274

[30] Foreign Application Priority Data Mar. 17, 1971 Germany 212854 [52] US. Cl. 340/373 R, 340/378 R [51] Int. Cl. G08b 5/24 [58] Field of Search 340/373 R, 378 R [56] References Cited UNITED STATES PATENTS 3,406,388 10/1968 Pihl ..340/373R 1 Jan. 29, 1974 3,465,333 9/1969 Pihl 340/373 R 3,543,202 11/1970 Naybor 340/373 X 3,553,619 l/l97l Skrobisch 340/373 X 3,555,419 l/197l Blacknell 340/373 X Primary ExaminerHarold L. Pitts Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin ABSTRACT The indicator consists of a coil wrapped around an iron core and a visual target which is rotatably and displaceably supported and which contains a permanent magnet. Upon reversal of the magnetic field in the iron core produced by the coil, the permanent magnet of the visual target is repelled, rotated 180 by the magnetic forces and again attracted. The new position of the visual target is thereby fixed, even if current no longer flows through the coil.

6 Claims, 4 Drawing Figures ELECTRO-MECHANICAL POSITION INDICATOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to position indicators and more particularly to electro-mechanical position indicators operating on magnetic principles.

2. Description of the Prior Art A multitude of position indicators are known, in which the magnetic field produced by a currentcarrying coil is used to move a visual target and to achieve, in this manner, an indication of two or more different states. Such a position indicator should have a visual target with defined end positions, so that a clear statement is obtained even if the magnetic field caused by the coil varies. The visual targets are fixed in 'the end positions by stops or latching arrangements of greater'or lesser complexity.

SUMMARY OF THE INVENTION It is the object of this present invention to design a position indicator with a movable visual target with two clearly defined static positions, in which neither a latching arrangement for locking the visual target in the end positions nor a continuous current-carrying coil is required. The position indicator of this invention consists of a movable visual target which contains a premagnetized, permanent magnetic material and a coil with an iron core upon which the visual target is rotatably and displaceably supported. When the magnetic field in the iron core is reversed, the permanent magnetic in the movable visual target is repelled, rotated 180 by the magnetic forces and again attracted. The new position of the permanent magnet within the visual target is thereby fixed, even if current no longer flows through the coil. The position indicator of this invention has the advantage that one of two opposite surfaces of the movable visual target always faces the viewer, so that there is no limitation as to the type of lettering and the color for each of the two possible positions.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the Electro-mechanical Position Indicator, partially in cross section.

FIG. 2 is another side view of the Electro-mechanical Position Indicator, partially in cross section, the cross section being in a plane approximately perpendicular to the cross section shown in FIG. 1.

FIG. 3 is a top view of the Position Indicator shown in FIG. 1.

FIG. 4 is also a top view of the Position Indicator shown in FIG. 1, showing the visual target after having been rotated 180 from the position shown in FIG. 3.

DETAILED DESCRIPTION Referring to FIG. 1, the Position Indicator consists of an iron core 1 disposed in a vertical position and having two insulating flanges 3 and 4. The upper insulating flange 3 is positioned at the top of the core 1 and the lower insulating flange 4 is positioned at the bottom of the core 1. the coil 2 is wound around the iron core 1. Optionally, a separate coil form (not shown) may be provided and the coil 2 may be wound around such separate coil form.

A U-shaped support bracket ,5 is positioned at the upper end of the coil 2 and fastened to the upper insulating flange 3. There are two elongated holes 6 and 7, one in each of the legs of the bracket 5. The longer axis of each elongated hole is positioned vertically. Each of the two pins 8 and 9 protrude into one of these elongated holes 6 and 7. These pins 8 and 9 are fastened in two opposite sides of the visual target 10 and rotatably support the visual target 10. Optionally, a trough shaft (not shown) could be provided instead of the two pins 8 and 9. The visual target 10 either contains a permanent magnet or consists entirely of permanent magnetic' material and has two opposing surfaces 12 and 13. OP.-

tionally, the opposing surfaces 12 and 13 may be flat, as shown in FIG. 1. The iron core 1 is perpendicular to the opposing surfaces 12 and 13 of the visual target 10. I

When the position indicator is installed, the coil ter mials 14 and 15 are connected to a dc source of elec;,

tricity. Depending on the direction of current flowing in the coil 2, a North pole or South pole is formed at the upper end of the iron core 1. If no current flows in the coil 2, the magnetization of the iron core 1 depends on the position of the visual target 10.

Assuming, for instance, that the North pole of the permanent magnet within the visual target 10 faces the iron core 1, a South pole would form at the upper end of the iron core 1 without current in the coil 2. The visual target 10 and the iron core 1 therefore attract each other.

If current flows in the coil 2 in such manner that a North pole is produced at the upper end of the iron core 1, the visual target 10 and the iron core 1 will repel each other. The elongated holes 6 and 7 guide the pins 8 and 9 and permit the visual target 10 to move away from the iron core 1. The displacement of the visual target 10 from the iron core 1 is limited by the length of the elongated holes 6 and 7. When the visual target 10' has reached the position of maximum displacement from the iron core 1, the visual target 10 rotates l, so that the South pole of the permanent magnet 11 within visual target 10 faces the iron core 1. The iron core 1 and the visual target 10 again attract each other, so that the visual target 10 returns to the position shown in FIG. 1. After the current in the coil 2 is disconnected, either the surface'12 or-the-surface 13 of the visual target 10 will therefore be in contact with the iron core 1, depending upon the direction of the current that last flowed through the coil 2. During the time that one of the surfaces 12 or 13 is in contact with the iron core 1, the visual target is in aposition substantially perpendicular to the iron core 1.

A top view of the surface 12 of the visual target 10 is shown in FIG. 3. The frame 17, which surrounds the visual target 10 from the side of the viewer, may be part of the display panel. Referring to FIG. 4, when the visual target 10 rotates the opposite surface 13 is displayed. Thus, for example, FIGS. 1 and 3 show the position of the opposing surfaces 12 and 13 of the visual target 10 when electrical current to the coil 2 is interrupted. FIG. 4 shows the position of the surface 13 when electircal current flows in the coil2.

The visual targetv 10 may be provided with different colors and appropriate marking symbols depending upon the function desired.

Referring to F IG. 1, a mounting stud 18 is provided for supporting the indicator. The mounting stud 18 is part of the core 1. In lieu of a mounting stud 18, it is, of course, possible to accommodate the indicator in a module of a mosaic panel of the type that is used in control rooms.

In the foregoing, the invention has been described in reference to specific exemplary embodiments. It will be evident, however, that variations and modifications, as well as the substitution of equivalent constructions and arrangements for those shownfor illustration, may be made without departing from the broader scope and spirit of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense.

What is claimed'is:

1. A visual indicator comprising: a magnetizible core about which a magnetizing coil is wound, magnetizing said core with reversing polarity dependent on the direction of direct current applied to the coil; an indicator device having opposite surfaces alternately engageable with an end of said core and permanently magnetized so that said surfaces are of opposite polarity; and means for rotatively mounting said indicator device for limited reciprocating motion relative to said core end so that when said coil is energized with the polarity of said core the same as that of the engaging surface of said indicator device the latter is pushed away therefrom, the limits of its reciprocation permitting it to rotate and to turn its surface of opposite polarity towards said core end and to be attracted to and retained in engagement therewith.

2. The indicator of claim 1 in which the opposite surfaces of said indicator device bear differing identifying indicia.

3. The indicator of claim 1 in which said means comprise a bracket having laterally interspaced arms extending away from said core end and in which correspondingly extending elongated holes are formed transversely, said indicator device having transverse pins positioned in these holes for reciprocation and rotation therein.

4. The indicator of claim 1 and further comprising a mounting stud connected to the core for supporting the indicator.

5. The indicator of claim 1 wherein the indicator device consists entirely of a permanent magnetic material.

6. An electro-mechanical position indicator according to claim 1 wherein the two opposite surfaces of the indicator device are flat.

I! i I 1R 

1. A visual indicator comprising: a magnetizible core about which a magnetizing coil is wound, magnetizing said core with reversing polarity dependent on the direction of direct current applied to the coil; an indicator device having opposite surfaces alternately engageable with an end of said core and permanently magnetized so that said surfaces are of opposite polarity; and means for rotatively mounting said indicator device for limited reciprocating motion relative to said core end so that when said coil is energized with the polarity of said core the same as that of the engaging surface of said indicator device the latter is pushed away therefrom, the limits of its reciprocation permitting it to rotate and to turn its surface of opposite polarity towards said core end and to be attracted to and retained in engagement therewith.
 2. The indicator of claim 1 in which the opposite surfaces of said indicator device bear differing identifying indicia.
 3. The indicator of claim 1 in which said means comprise a bracket having laterally interspaced arms extending away from said core end and in which correspondingly extending elongated holes are formed transversely, said indicator device having transverse pins positioned in these holes for reciprocation and rotation therein.
 4. The indicator of claim 1 and further comprising a mounting stud connected to the core for supporting the indicator.
 5. The indicator of claim 1 wherein the indicator device consists entirely of a permanent magnetic material.
 6. An electro-mechanical position indicator according to claim 1 wherein the two opposite surfaces of the indicator device are flat. 